The present invention relates to a process and apparatus for making continuous exothermic chemical reactions between solid, liquid or gaseous products so as to obtain a final dry solid product having a (free water content less than 6% for inorganic products) with the following main characteristics:
(1) The reaction medium remains permanently in solid phase of dry appearance with a (solid in suspension in a gaseous medium, hence limiting any risk of soiling).
(2) At all times, the different products contained in the
reaction phase remain in proportions close to the stoichiometric conditions of the desired reaction, hence limitation of undesirable intermediate or parasitic reactions. PA1 by monitoring the flow rates of raw materials coming into reaction (this may be done by monitoring temperature since any variation in temperature in the reactors immediately indicates any variation of the flowrates and characteristics of the raw materials). PA1 by the initial choice of the exothermic level of the reactions chosen since different reactions of exothermicity may be carried out simultaneously in the reactor, for example: reaction of phosphoric acid with quick lime, simultaneously with the reaction of said acid with calcium carbonate. PA1 limit fly-off of solid materials; PA1 to allow them to be treated dry using a cyclone and bag filter, avoiding any loss of product, considerable corrosion, and pollution and thereby sequently simplifying the treatment apparatus.
(3) The reaction carried out generally leads to the information, in addition to the desired solid product, of gaseous compounds such as water vapour, CO.sub.2, etc., which contribute under the reaction conditions and to a large extent to the suspension and fluidization of the reaction mass.
(4) The additional mechanical energy for effecting this suspension is very low due to the considerable fluidity of the reaction mass.
(5) The reaction temperature is constant and may be taken to the desired optimal level, enabling stable reaction conditions and high reaction speeds to be obtained, and thus:
(6) The apparatus further promotes the evacuation of the gaseous compounds obtained, consequently increasing tenfold the chemical balances in the desired sense.
The conditions of evacuation of the gases furnished, associated with stabilization of the operational parameters of the reactor, are such that they are easily adjusted in order:
(7) Taking the foregoing parameters into account, the reactor is of small dimensions employing small quantities of products, thus rendering heat losses low and giving an excellent thermodynamic yield. The cost of the raw materials is consequently optimalized.
For example: in the case of reacting an acid on a mixture of CaO and CaCO.sub.3, the proportion of CaO, expensive raw material, is substantially reduced, while that of CaCO.sub.3 is increased.
(8) The powders obtained have the advantage of being easy to granulate subsequently.